The present invention relates to a take-up cassette for web-type recording medium, having a motor driven take-up roller with a core that is provided with a mechanism for capturing the leading edge of media in the core of the roller when winding the media and for releasing the leading edge of media when unwinding the media.
The invention is an improvement over non-powered scroll style cassettes, in which media is simply pushed into a loose spiral of a cylindrical chamber. As the media is pushed into the loose spiral, the diameter of the cylindrical chamber expands. There are several problems with) this type of take-up cassette. For instance, the scroll style cassettes have a limited inner diameter in which it is difficult to get a tightly wrapped roll of media, limiting the take-up capacity. Also, the soft photographic emulsion coating on film types of media is prone to scratching as the advancing media slides against itself as it coils within the spiral. Further, the electrically insulated properties of typical spiral material, such as plastic coated spring steel; enhance the build up of static charges on the media as it is pushed into the take-up cassette. Lastly, the force required to feed the media into the take-up cassette increases as the cassette becomes full, influencing the performance of the media transport system.
Media cassettes of the motor driven type have an advantage over the above spiral type take-up cassettes, in that the media can be tightly wound on the core of a motor driven take-up roller with the result that a greater quantity of media can be fed into a comparable size cassette. Also, the layers of media do not slide against each other as they do when the media is pushed into a spiral type cassette, thus decreasing the potential for scratching and electrostatic build-up.
It is a general object of the invention to provide a motorized take-up cassette that can be used without adjustment for width or thickness when using common imaging media such as paper or polymer based photographic and photolithographic graphic arts media including direct-to-plate materials.
Another object of the invention is to provide an automatic take-up roller that is capable of capturing a leading edge of a continuous recording medium when the recording medium is wound around the take-up roller, and that is capable of releasing the leading edge when the recording medium is unwound from the take-up roller.
It is a specific object of the invention to provide a clamping mechanism of a take-up roller with means to prevent material from slipping out from the clamping mechanism during winding.